Over the past two weeks, Japan’s Nuclear Regulatory Authority has revealed the specifics of their proposed new rules for nukes. The changes are long-overdue and promise to be sweeping. Japan’s prior regulatory philosophy was to leave the implementation of proposed safety changes and/or upgrades up to the utility companies that own and operate the power stations. If the utilities could come up with reasonably sound rationales for not making changes, the recommendations were virtually ignored. As a result, Japan’s nuclear safety program became stagnant. The new rules, however, will carry legal weight with them. Instead of asking the utilities to make changes, they will be told!
In Japan’s pre-Fukushima era, there were essentially two over-lapping reasons for rejecting recommended safety upgrades. First, many suggested changes were intended to mitigate the possible effects of very low probability accident precursors. For example, the tsunami protection surrounding Fukushima Daiichi (a robust property-encompassing sea wall about 25 feet high) was based on the biggest wave which had occurred over the previous 450 years. The tsunami-protective structures for all cities and towns along the Tohoku coast were protected by various man-made barriers based on the same historical criterion. While there was some historical evidence indicating there was a 40-50 foot-high wave nearly 1,000 years ago, the evidence was considered inconclusive. Plus, even if the ancient tsunami had firm scientific support, the once-per-millennia event was too infrequent to be seriously considered.
Second, there was the issue of cost. What kind of investment would have to be undertaken to meet the suggested criteria? If the projected cost for the upgrades was considered too great for the possible safety benefit that might ensue, the change could be rejected by the utility involved. Tsunami upgrades addressing the rare-but-not-impossible millennial wave would have required more massive sea-walls and/or shoreline dikes, mobile back-up power generators, and waterproofing the rooms that housed the emergency diesel generators and batteries. This was judged by most utilities to be not worth the money.
In hindsight, if the allegedly too-costly recommendations from the IAEA and America’s Nuclear Regulatory Commission had been made at F. Daiichi in the early part of this century, the tsunami of 3/11/11 would probably not have caused the multiple-meltdown nuclear accident. How can I say such a thing? We need only look at Fukushima Daiini 10 kilometers south of F. Daiichi and the Onagawa station 120km north of F. Daiichi Onagawa was closest to the epicenter of the tsunami spawning quake and experienced the most severe ground motion. Both stations survived unscathed, and if it were not for Japan’s current nuclear moratorium, both would be safely operating and mitigating Japan’s current energy-shortage. The existing tsunami barriers at both were more than adequate to prevent a complete loss of power.
It must be added that not all of Japan’s utilities rejected all of the suggested upgrades covering the rare-but-not-impossible accident precursor. The Onagawa nuclear station decided to erect protective shoreline dikes more than 50 feet high….just in case. The tsunami of 3/11/11 hit the barrier with a 30 foot swell, and the dike held. In fact, hundreds of local shoreline residents near Onagawa evacuated to the nuke site and were given free food, water, and make-shift living quarters until the waters subsided. Onagawa nuclear station was the safest place to be on 3/11/11. If F. Daiichi had built a 50-foot sea-wall, it is possible the accident would have been averted.
There can be no doubt that Japan’s pre-Fukushima regulatory system failed. The rare-but-not impossible accident precursors must be accounted for. The cost of safety upgrades can no longer be allowed to exist as a rationale for non-compliance. The NRA says they are using America’s Nuclear Regulatory Commission as their model of change – and by all accounts they are doing exactly that. The NRA clearly believes that the US NRC is the better regulatory mousetrap. Prior to 3/11/11, I was a critic of the NRC, believing that the agency was unnecessarily impeding the growth of the one energy source that can best avert a worst-case global warming scenario. My attitude has changed considerably. Not that the NRC is without its warts and wrinkles. As long as the non-scientific Linear/No Threshold assumption is used to mandate public protective measures (such as evacuation distances), low level radiation exposure will remain an unnecessary, irrational fear in the minds of millions of present and future Americans. Regardless, there can be no better regulatory model than the NRC for Japan’s new nuke watchdog.